Tonometer



' I. GOLDSTEIN.

TQNDMETER. APPHCATION FILED JULY'OI 1920.

' ATTORNEY Patented June '13, 1922 mm llll ilhlilttt: STATES PATEN T orrics 1:

ISADORE GOLDSTEIN, F YORK, N. Y.

TONOMETER.

Specification of Letters .Patent.

Patented June 13,1922.

Application filed July 10, 1920. Serial No. 395,366.

' ventec a new and useful Tonometer, of which part of the application,

the following is a specification.

The invention is an improvement in :tonometers, which are instruments for determining the tension of the eyeball, or the pressure of its fluid contents upon its walls, in glaucoma. The original method of palpating the eyeball by the finger tips was uncertain, and the instruments of the lever type which have been employed are only approximately accurate. The object of this invention is to provide a delicate, accurate andeasily read instrument for the purpose, utilizing a liquid, as mercury, which is displaced in a capillary tube in accordance with the counterpressure of the eye when the instrument is allowed to rest, by its foot and a relatively movable plunger, upon the eye ball.

In the accompanying drawings, forming a and illustrating the present preferred embodiment of the invention:

Figure. 1 is an elevation of the instrument;

Fig. 2 is a vertical section on a larger scale, looking at right angles to Fig. 1, and with the tube broken away, full lines being used to show the normal projecting condition of the plunger before it has been applied to the eyeball, and dotted lines showing the plunger relatively raised until it touches the diaen phragm, which is the beginning of the indicating movement; and

Fig. 3 is a horizontal-section on the line 3--3 of Fig. 2. v

The instrument may be varied in respect to form and detailsof construction, and it will therefore be understood that I do not limit myself to the particular embodiment which will now be briefly described. The body of the'instrument includes a member 1 having a broad, cup-like upper portion, and a downwardly projecting hollow stem 2, terminating in an expanded foot 3, the bottom 4 of which is concaved to conform substantially to the curvature of the eyeball. The upper portion of said member is formed externally with vertically spaced lateral'fianges or shoulders 5, between which is loosely confined an encircling holder 6, having suitable handle or grip portions 7 at opposite sides. This holder, having acertain vertical freedom between the flanges, enables the operator to sustain the instrument laterally so as to rest in a vertical p0sition on the eyeball, without the hand applylng pressure thereto or removing it there; from, so as to afiect the reading. For convenience in assembling, the holder may be made in two halves, secured together by:

screws 8.

The cup 1 is internally screw-threaded at thetop to receive a'second member, or nut, 9. i118 nut is concaved on the under side to afford a mercury reservoir 10, the bottom of which is formed by a flexible wall or diaphragm 11. Said diaphragm may be secured to the nut by a flanged screw ring 12, with gaskets 13 at opposite sides of the margin of the diaphragm, between the same and the ring and the nut, respectively, to prevent leakage.

Thenut 9 is also formed with a, central opening, the upper part 14 of which is of relatively large diameter and internally screw-threaded, while the lower part has a small hole 15, opening into the top of the reservoirat its highest point. An upright tube 16 of glass or other transparent mate rial, having a capillary bore, is secured, with a leak-tight joint, at its lower end, in the chamber 14, by a gland nut 17 and packing rings 18 and 19, encircling the tube and between the end of the same, and the bottom of the chamber, respectively.

The upper end 20 of the tube is open, and larged to form a funnel entrancefor fluid to charge the reservoir and column.

A plunger 21 passes through the stem 2 and foot 3, in which it is slidably guided. Its upper end is provided with a suitable head 22 to act upon the diaphragm, said head being made of a separate piece screwed upon the body of. the plunger so that the plunger length can to say with the instrument, held vertically and not resting on the eye, the plunger is sustained with its lower end projecting a moderate distance so as to guide the application to the eye-ball, and its upper end se arated a distance ,from the diaphragm. imple means for this purpose comprise a transverse pin 23 in the stem, passing through a vertically extending slot 24 in the plunger, this slot being of such length and so positioned that, when its upper end rests upon the-top of the pin, the conbe adjusted. Normally, that is form a sight to dition indicated obtains, while atter the plunger has been raised until it touchesthe of indication. The

contacts with the diaphragm.

A scale, or scales, are prov dedwhereby q the condition of the eyeball is read directly in millimeters of mercury from the: vdisg placement of the top of the column in the glass.

be applied directly to the tube, or a, separate adjustable scale 26 may be mountedyon. a

against the bottom of the diaphragm en ables the column to be adjusted for normal bined witha plungermovable through; the

vertical screw-threaded rod 27 rising from] the nut member 17, nuts 28 on therod above and below the movable scale: enabling the same to; beheld at any desired elevation A thumb-screw 29 threaded through thebotw tom oi the member 1: in "position to bear or zero position. Thediaphragm lllmay be resilient or non-resilient and may bel nor-i and the scales may a graduated. of the headwotthe column, which serves astheindication, isipro duced by the movement of theplungerlrelatively to the foot, after the headfijof; the; plunger has been brought against the dia phragnrby contact with the eyeball. Therethe degree to which the-fplunger,v bear I mally fiat or may sag; be uniformly or .non- 'uniformly The displacement er ing its proportion of the weight of lthe instrument, sinks into, orjis \resisted bytthe v; eyeball, while the expanded and concavedv foot of the instrument rests thereonpis the measure of the; tension; of the eye; and 1s registered by a lesser or greater rise ofthe column in the glass. I t Whatl claim as new is; a

1. A tonometer compr sing a foot adapted to rest on the eyeballga res:

ervoir having a diaphragm forming its, bottom, a reservoir, a scale, through the foot phragm. a i

2. In a tonometer, a body'havinga, foot to rest upon the eyebalha reservoirl having a flexible wall, a glass ti1be -in communica tion with the reservoir, and a rscale, com-I to act upon saidzvdia-v foot and normally, sustained in projecting condition operatively separated from I the flexiblewall, i a v 3,. In a tonometer, the cornbina'tionot a body having a foot tofrestupon the eyeball,

a reservoir having a diaphragmjformingits bottom, a glass tube in communication with themreservoir, a plunger movable through the foot, and means normally sustaining l the plunger in downwardly dition with space between; its upper end projecting con and the diaphragm.

" genhormafly resting by gravity. away A suitably graduated; scale, "25 ma-y b a diaphragm securedto saidlsecond, meme; her; iIIlClfOI'lll-lllg the bottom of: the reservoir,

portion, of saidabody member [havmgvertically spaced lateral flanges, a .jholderens circling; the body member loose between said I fianges aqre'servoir in said body "member: jfl havingqa diaphragmbottom;a tube sup, j: glass tube in communicationwith the 11 0 and 'a plungerw movable,

the plunger canbe varied. 1 1

ing a diaphragm-forming its bottom, a glass tube fin communication withjthe reservoir, ascale, and a plunger movable throughlthe foot to act upon said diaphragmpthe plunfrom t phrasm-wt downward y 1 projecting stem terminating in fiXedfin the wide upperportion of said body member and havmgaf central opening and a being recessed beneath to form a reservoir;

a tube secured in communication with the centralopeningofthe secondmembenand 1 'v a plungerglslidable through the stem and foot to act on thejdiaphragm.-* r 1 ;6. A. Jtonometer compr sing a body meinberfhaving a wide "upper portionand downwardly. projecting stem terminating in; afifootmto rest on the eyeball, a nut screwed in the top ,ofsaid member and hfiV?" ing a central opening and i being ,concaved at the bottom, ita diaphragm secured to said concaved' bottom and J forming; therewith a .I

tion withthe opening of rthe,nut,a plunger slidable through "the" stem anda fOOttOi act;

on the diaphragm, and a pin in thestem reservoir, a tube securedgin communica:

normally sustaining the plunger separated lilO i th'e diaphragm, Y

7 A tonometer, compr sing a berhaving a wide upper portion and a downwardly 1 projecting stem 7 terminating in a foot to rest onthe eyeball, thel up'per ported in communication a with i said reservoir, and al plunger slldable "through the stem and foot to act uponthe diaphragm;

8. In a tonomete y ja bodyfhavingsa foot bined v with m a plunger movable tln'ougljijthew e ys a ned in PlTOififitingfl a a .condition OPGIatiVBlyv.sepa t d f m a means whereby th j h f a 9 tonometer comprisingabody i a foot to rest onthe eyeball, a reservoir hfLVr iingwa diaphragm forming its bottomg a 125 plunger movable through 1' glass tube in communication t with the res-g ervo r, scale, a

the foot toyactuponj sa1d diaphragm, and

dj ns m ans ti e upon th aph m-v ISAD RE en smm j 5. Artonometer comprising a body member havin a wide upper portion and a 

